You can use spell tag in Text Speaker to spell out the letters in a word.

Open Text Speaker and enter the text you want to read. Select the word ‘SAT’ from the sentence, go to the Edit menu and choose ‘Spell Selected Word / Phrase’ option. The letter will be surrounded with the <spell> tag like this <spell>SAT</spell>.

Click the ‘Speak’ icon on the tool bar to hear the sentence read aloud with the word SAT spelled out.